A bar bending schedule (BBS) is prepared from the structural drawings for each member: footings, columns, beams, slabs. For every bar mark it shows the diameter, shape with dimensions, cutting length, number of bars and total weight. The bar bender cuts and bends from it, and the office uses it to order and check steel.
Cutting length is the straight length before bending, so it allows for hooks, bends, laps and cover as per the drawings and the code or standard the project follows. Errors here show up as short bars on site or extra steel in the scrap pile.
Weight per metre for a bar is commonly worked out as diameter² ÷ 162 (diameter in mm, result in kg per metre). Total BBS weight is a useful check against steel issued in material reconciliation. Get the BBS checked by the engineer before cutting starts, since a wrong length repeated across many bars wastes a lot of steel.
Example
Illustrative: 20 bars of 12 mm, cutting length 3.5 m each = 70 m. Weight = 12² ÷ 162 ≈ 0.89 kg/m, so about 62 kg.
